longenecker



Feb. 21, 1956 Filed Dec. 3, 1952 L. s. LONGENECKER FURNACE DOORS AND SEALS 4 Sheets-Sheet l INVENTOR. Lew .S. Longenec/rer MMIMW W HIS ATTORNEYS 4 Sheets-Sheet 2 L. S. LONGENECKER FURNACE DOORS AND SEALS Feb. 21, 1956 Filed Dec. 3, 1952 m IIIFLIIIIIFLIII INVEN TOR. L em 5. L ongenecker BY 9. m 1141 H/S A TTORNE Y5 Feb. 21, 1956 s. LONGENECKER 2,735,386

FURNACE DOORS AND SEALS Filed Dec. 3, 1952 4 Sheets-Sheet 3 HIS A T TOR/V575 21, 1955 L. s. LONGENECKER 2,735,386

FURNACE DOORS AND SEALS Filed Dec. 3, 1952 4 Sheets-Sheet 4 INVENTOR. Lew 5. Longeneclrer B MW HIS A TTORNE Y5 2,735,386 FURNACE DOGRS AND SEALS Levi S. Longenecker, Mount Lebanon, Pa. Application December 3, 1952, Serial N 0. 323,876 13 Claims. (Cl. 110-476) This invention relates to furnaces of the all-door front wall construction and more particularly to the doors, the seals and the door and seal operating mechanisms of such furnaces.

Prior to my invention of a. tilt-lift door, no all-door front wall metallurgical furnace was constructed so far as I know and I am sure that none was ever operated successfully.

It is my belief that the doors of all metallurgical furnaces prior to the advent of the tilt-lift door were mounted and operated in such manner as to slide on the furnace walls and door jambs as they were raised and lowered. This mode of operation required considerable power to overcome friction occurring between the sliding surfaces and subjected the linings of the doors as well as the door jambs and arches to considerable wear and damage.

A number of furnaces of the all-door front wall type equipped with my tilt-lift doors have been in operation for a number of years. These doors are of necessity spaced apart, although arranged in side by side relation and require seals for closing the spaces between adjacent doors and between the end doors and the door jambs. Most of the tilt-lift doors have been similar to the air cooled or dry door disclosed in my Patent 2,387,594. Most of these have embodied the pilot truck of my Patent 2,494,713 and have been operated in accordance with the teachings of that patent.

Numerous types of seals have been used with these tilt-lift doors, but the type disclosed in my Patent 2,594,188 has been found to be the most satisfactory for this type of door.

I have found that seals of any type when used with tilt-lift doors may be a source of trouble especially if the doors are used on an open hearth furnace.

An object of this invention is to produce an improved door which is particularly adapted for use in all-door front wall furnace structures.

Another object is to produce an improved furnace for use in all-door front wall furnace structures; improved operating means for such doors, and door seals which are connected to such operating means and which while they are raised and lowered by the doors, as first broadly disclosed in my Patent 2,045,662 of June 30, 1936, will be free from the troubles heretofore encountered in all seals used with tilt-lift doors.

These and other objects which will be skilled in this particular art, l attain by means of the structure described in the specification and illustrated in the drawings accompanying and forming part of this application.

In the drawings:

Figure 1 is a view in front elevation of a furnace equipped with three doors embodying this invention arranged side by side in slightly spaced relation; each door being equipped with a door operating mechanism. The seals of this invention for closing the spaces between apparent to those 2,735,386 Patented Feb. 21, 1956' 2. adjacent doors and between the end doors and the door jambs are also shown.

Fig. 2 is a fragmentary top plan view on an enlarged scale of the left-hand door of Fig. 1 and a part of the next adjacent door, and shows the top of two of the seals;

Fig. 3 is a fragmentary view in front elevation of the upper part of the structure of Fig. 2;

Fig. 4 is a side view in elevation of a water cooled door of this invention in its normal tilted toward the furnace position. In this view the door is shown resting on the sill of the furnace and in contact with the door lintel;

Fig. 5 is a view similar to Fig. 4 and shows thedoor raised to full open position;

Fig. 6 is an enlarged view in sectional elevation of the door of Figs. 1, 4 and 5;

Fig. 7 is a section taken on line VII-VII of Fig. 6;

and

Fig. 8 is a diagrammatic illustration of the door of this invention and its operating mechanism; the seals and various details being omitted.

The furnace chosen for the purpose of disclosing this invention employs a series of three doors with the spaces between adjacent doors and between the end doors and the door jambs sealed by sealing members such as broadly disclosed in my Patent 2,045,662 of June 30, 1936.

It is to be understood that in the specification and claims when the term hoisting line or lines is employed, it is merely for the purpose of convenience and such terms are intended to include chains as well as cables.

While I have disclosed water cooled doors in this application, it will be understood that in many cases dry doors such as disclosed in Patent 2,387,594 issued to me on October 23, 1945 will preferably be utilized in place of water cooled doors.

Each door of the series is arranged to be permanently tilted toward the furnace at all times and each is operated by its own hoisting mechanism which is identical for all doors of the series.

In order to keep the bottom of the doors and their seals in proper position with relation to the buckstays and provide a satisfactory door tilt, the conventional skewback channel when used must be spaced inwardly from the buckstays a greater distance than required for tilt-lift doors. In this case, the door lintel is spaced inwardly from the buckstays a distance of more than 12 inches in order to permit a satisfactory door tilt. The doors as shown in Figs. 4 and 6, when in closed position, rest on the door sill and contact the door lintel lightly. The doors a, b and c making up the series of three of this application are spaced apart, that is, doors a and c are spaced about two inches from door 12. Doors 11 and c are also spaced about two inches from the door janbs iii and 1 major part of the side edges of the refractories of such doors are exposed.

The spaces between door b and doors a and c as well as the spaces between doors a and c and the door jambs it) and ii are covered or sealed when the doors are in closed position by seals 12 which are generally L-shaped the long legs of the L covering the off-furnace side of these gaps, while the short legs cover the tops of the gaps (Figs. 4 and 5).

A track comprising rails 13 extends vertically above each door. These tracks. are secured to the furnace front structure and extend from the water cooled lintel 14 a distance above the upper limit of travel of the tops of the doors when in their fully raised position.

Extending upwardly from the. top of each door adjacent its opposite ends on its furnace side are two wheel sup- This is necessarily so because the 3 port standards 15. Each of these adjacent its top is provided with a horizontal headed bolt-like member 16, see Figure 2, which is adapted to carry a flanged wheel 17. The diameter of wheels 17 and their distance above the door is such that when the door'is in down position resting on sill 18, wheels 17 contact track rails 13 so that the upper part of the door lightly contacts the water cooling tubes of lintel 14.

Located above the upper end of each track is a horizontal shaft 19, see Figure l, which is journaled for rotation within suitable bearings 20 supported in standards 21-21 secured to the furnace superstructure, preferably in such position that the axis of shaft 19 is directly above one of the tracks 13. Each shaft 19 has four sheaves, 22, 23, 24 and 25 of equal diameter keyed thereto. Chains 26-26 are secured to sheaves 22 and 25 and to fixtures 27-27 which are attached as by welding to an I-beam 28 which is secured, as by welding, see Figure 4, to the front or elf-furnace side of the door adjacent its top. I-beam 28 throughout the major part of its length between fixtures 27-27 is covered by an angle iron 29, see Figure 3. I-beam 28, fixtures -7-27 and angle iron 29 are all welded together and to the front member 30 of the door structure. Sheave 23 which is located midway between sheaves 22 and 25 has secured thereto a chain 31. The lower end of chain 31 is provided with a hook 32 which engages a pin 33 which extends through two short sections of channels 34 which are arranged back to back, so to speak, and are spaced apart and secured to the door top at its longitudinal center on its furnace side.

Each of chains 2626 and 31 is provided with a length adjustment turnbuckle 35, see Figures 4 and 5.

Chain 36 is secured to sheave 24, as shown in Figures 1 and 8, and is wrapped around such sheave in the opposite direction from the other chains and leads across the furnace and down to an electrically operated hoist 37 preferably such as disclosed in my Patent 2,494,713. In cases where the door seal and door operating mechanism of this invention are to be utilized on an open hearth furnace, the hoisting device 37 will preferably operate without a counterweight and for that reason the hoists have to be large enough to handle the load alone, that is, without a counterweight.

Where the doors whether dry or water cooled are to be employed in connection with a furnace where there is suflicient room for a counterweight, I prefer to use a counterweight somewhat along the line disclosed in my said Patent 2,494,713 and thereby cut down the size of the hoisting device.

Figure 8 schematically discloses a hook-up without a counterweight.

Dash line 38 of Figure 1 represents the top of the furnace opening or bottom of the lintel 14.

The permanent tilt of each door is controlled by the two chains 26-26 secured to its off-furnace side adjacent its ends and chain 31 which is secured adjacent the furnace side of the door adjacent its longitudinal center. These chains, that is, chain 31 and the pair of chains 26, straddle the center of mass of the door and the tilt of the door is controlled by adjustment of the turnbuckles in these chains which not only control the door tilt but snub the door against swinging. Proper adjustment between the two chains 26 keeps the door in level position. Both the level control and the stabilizing are necessary for successful operation of any set-up in which the doors are in consecutive arrangement and operated edge to edge with but a small space such as two inches between such edges.

The wheel flanges prevent the doors from twisting on their chain supports and also prevent them from walking sideways and fouling adjacent doors.

Sheaves 22, 23, 24 and 25 for each door are of the same diameter and if desired, can be replaced by a drum of uniform diameter which would raise all three chains of each door the same distance and at the same speed.

Each seal 12 at its top on its oif-furnace side is provided with a cross arm 39 which is provided at its opposite ends with openings 40 through which chains 26 of adjacent doors pass, see Figures 2, 3 and 4. That is, each chain 26 before being secured to its fixture 27, is passed through one of the openings 40 in the adjacent cross member or keeper 39. Because of this arrangement, the simple type seals are held in place and are carried up and down by means of the short right-angled top legs which overlap the top of the space between adjacent doors; the seal being carried by whichever door is uppermost.

Since the clearance space between the doors is closed by the door seals, I locate wicket or peep-holes in the door edges as shown at 41 in Fig. 1. In order to use these peep-holes, the operator swings the long leg of the seal to one side and when his observation is finished, he swings the seal back to normal position. Wicket holes are only used when the doors are in closed position and when in closed position, the wicket holes are covered by the seals. In prior water cooled doors, the wicket holes are located in the bottom center of each door and considerably reduce and weaken the refractory lining at that portion of the door where wear and tear are the most severe.

Since the tilt of the doors is not affected by the lining thickness and since the doors are always in tilted position, the bottom part of the lining can be thicker than the top part in order to offset the more severe wear adjacent the furnace hearth. In this application, the top part of the lining is shown as 9 inches thick while the bottom part is shown as 12 inches thick. Dash line 42 of Figure 6 is a vertical line which includes the outermost point of lintel 14 and this line clearly shows that point 43 of the topmost twelve inch brick would clear the lintel while the door is being raised to full open position, the position shown in Fig. 5.

In order to prevent the doors from falling outward, should its hoist become unloaded and also to prevent the wheels 17 from disengaging the track, I provide the short channel sections 34-34 with oppositely directed booklike members 44-44, see Figures 2 and 3. These are bolted to the upper flanges of the adjacent members 34-34 by suitable bolts 45 and loosely embrace flange 46 of an I or H beam which parallels the track rails 13, is secured midway therebetween to the upper structure of the furnace and is preferably of the same length as the track rails 13.

What I claim is:

1. In combination in a furnace having a charging opening in its front wall, at least two doors for such opening and which are spaced apart and arranged side by side, a track extending vertically above each such door, wheels secured to the top of each such door, being arranged to engage the track and having their axes of rotation fixed with relation to such door, independent mechanism for raising and lowering each such door and holding the same tilted inwardly-upwardly while being raised and lowered and in its closed position, each such mechanism comprising rotatable winding means above the upper end of one such track, two chains secured to each such winding means and to the door therebelow adjacent the ends of its top adjacent its off-furnace side, and at least one chain secured to said winding means and to said door top at its center adjacent its furnace side, a generally L-shaped seal overlapping the front and top of each space between adjacent doors, each such seal having a cross arm provided with openings adjacent both its ends through which adjacent chains on the off-furnace side of adjacent doors extend.

2. A structure as defined in claim 1, in which each door a short distance above its bottom is provided with grooves on opposite sides thereof which are open to the spaces between the adjacent doors and which together with such grooves are covered by the long legs of the L-shaped seals which overlap the front and top of the spaces between such doors; the construction and arraugement being such that said grooves on the opposite sides of said doors provide peep-holes that are normally closed when the doors are closed by the long leg of such seals which can be swung sideways by the furnace operator to uncover such peep-holes and then swung back to cover the same.

3. In combination with a furnace having a charging opening in a wall thereof and a door sill along the bottom of the charging open n Of at least a pair of doors arranged in a side-by-side spaced-apart relationship for controlling such opening and which rest on the door sill when in a closed position, a track extending vertically above each of said doors, wheels operatively carried by a top portion of each of said doors to ride on the track thereabove, independent mechanisms for raising and lowering each of said doors; each of said mechanisms comprising rotatable Winding means directly positioned above said doors, a set of three chains for each of said doors operatively and directly connected at one end to said winding means, two chains of each'of said sets being directly secured to a top portion of one of said doors adjacent its off-furnace side, the other chain of each of said sets being directly secured to the top portion of one of said doors at substantially its center adjacent its furnace side, the three chains of each of saidsets being of proportioned lengths to position their respective doors in an upwardlyinwardly tilted relationship with the'furnace when the door is raised and lowered and in a closed position on the door sill, and means to positively retain said door in such tilted relationship during its usage.

4. The combination with a furnace having a charging opening in a wall thereof, of a door for controlling the opening, a track extending vertically above said door, wheels operatively mounted on the top portion of said door to engage said track, rotatable winding means, means for operating said Winding means, means secured to said door and said winding means for raising and lowering said door, said means for operating said winding means having portions at all times suspending said door in an upwardly-inwardly tilted relationship with respect to the furnace while said door is being raised and lowered and while it is in a closed position, means for retaining said Wheels on said track comprising a vertically-extending flanged retaining member secured to the furnace and paralleling said track, and means secured to the top of said door and embracing the flange of said retaining member.

5. The combination with a furnace having a charging opening in a Wall thereof, of a door for controlling the opening, a track extending vertically above said door, wheel means operatively secured to the top of said door to engage said track, rotatable winding means operatively positioned with respect to said door, means cooperating with a top portion of said door and at all times positioning it in an upwardly-inwardly tilted relationship with respect to the furnace, said last-mentioned means having portions operatively connected between said, winding means and said door to raise and lower said door in its tilted relationship, said last-mentioned means including safety guide means, and said safety guide means having operatively associated portions mounted on the furnace and on said door to retain said wheel means in a cooperating relationship with said track.

6. The combination with a furnace having a charging opening in a wall thereof, of a door for controlling the opening, a track extending vertically above said door, wheel means operatively secured to the top of said door to engage said track, rotatable winding means operatively positioned with respect to said door, means cooperating with a top portion of said door and at all times positioning it in an upwardly-inwardly tilted relationship with respect to the furnace, said last-mentioned means having chains operatively connected between said winding means and said door to raise and lower said door in its tilted relationship, seals positioned along top and side portions of said door to be raised and lowered with said door, a pair of said chains being connected to the side portions of said door, and said seals having portions encircling said pair of chains to guide said seals thereon.

7. The combination in a furnace having a charging opening in a wall thereof and a door sill along a portion of the charging opening, of at least a pair of doors arranged in a spaced-apartside-by-side relationship for controlling said opening and which rest on the door sill'in their closed positions, a track for each of said doors comprising a pair of rails extending thereabove, wheels secured to top portions of each of said doors for operative positioning at all times with its respective track, winding means positioned for operating said doors, means cooperating with a top portion of each of said doors to at all times position it in an upwardly-inwardly tilted relationship with respect to the furnace, said lastvmentioned means having portions operatively connected between said winding means and said doors to raise and lower them in their tilted relationships, seals positioned to cover top portions of said doors and off-furnace sides of the spacing between said doors, and said seals having means cooperating with said portions of said last-mentioned means to hold said seals in an aligned position-with respect to the spacing.

8. The combination ina furnace having a charging opening in a wall thereof and a door sill along a bottom portion of the charging opening, of at least a pair of doors arranged in a spacedrapart side-by-side relationship for controlling said opening .and which rest on the door sill in their ciosed positions, a track" for each of said doors comprising a pair of rails extending thereabove, wheels secured to top portions of each of said doors for operative positioning at all times with its operative track, winding means positioned for operating said doors, means cooperating with a top portion of each of said doors to at all times position it in an upwardlydnwardly tilted relationship with respect to the furnace, said last-mentioned means having portions operatively connected between said Winding means and said doors to raise and lower said doors in their tilted relationships, said portions of said last-mentioned means comprising a pair of side-positioned chains for each of said doors, and a seal for each of said doors having a cross member at its top with open portions near its ends through which said chains extend.

9. The combination with a furnace having a charging opening in a wall thereof and a door sill along the bottom of the charging opening, of at least a pair of doors arranged in a side-by-side spaced-apart relationship for controlling such opening and which rest on the door sill when in a closed position, a track extending vertically above each of said doors, wheels operatively carried by a portion of each of said doors to ride on the track thereabove, independent mechanisms for raising and lowering each of said doors; each of said mechanisms comprising rotatable winding means above said doors, a set of three flexible supports for each of said doors operatively connected at one end to said winding means, two supports of each of said sets being secured to a top portion of one of said doors adjacent its off-furnace side, the other support of each of said sets being secured to the top portion of one of said doors at substantially its center adjacent its furnace side, the three supports of each of said sets being of proportioned lengths to position their respective doors in an upwardly-inwardly tilted relationship with the furnace when the door is raised and lowered and in a closed position on the door sill, each of said doors having a top seal and a common side seal extending along and closing off the spacing between adjacent doors, and said side seal being positioned for guided movement on adjacent side supports of said doors to engage with at least one of said top seals for raising and lowering with the door of said top seal.

10. The combination with a furnace having a charging opening in a wall thereof, of a door for controlling the opening, a track extending above said door, wheel means operatively secured to the top portion of said door to ride on said track, winding means positioned for operating said door, means cooperating with a top portion of said door to support and raise and lower it with respect to the furnace opening, and said last-mentioned means having portions connected between said winding means and said door and having portions positively retaining said door on said track.

11. A combination as defined in claim 10 wherein said portions for retaining said door on said track are connected to the top portion of said door and positively retain said door in an upwardly-inwardly tilted operating relationship on said track.

12. The combination with a furnace having a charging opening in a wall thereof, of at least a pair of doors for controlling the opening, a track extending above each of said doors, wheel means operatively secured to the top portion of each of said doors to ride on said track, winding means positioned with respect to each of said doors, operating means cooperating with a top portion of each of said doors and with said Winding means to support and independently raise and lower each of said doors, seals for said doors positioned therealong to close off the charging opening when said doors are in a lowered position with respect thereto, and said seals having portions cooperating with said operating means to hold said seals in an aligned position with respect to said doors.

13. The combination with a furnace having a charging opening in a wall thereof, of a door for controlling the opening, a track extending above said door, wheel means operatively secured to the top portion of said door to ride on said track, a drive shaft operatively positioned directly above an upper end portion of said track, a series of winding drums operatively positioned on said shaft for actuation thereby, a set of three chains for said door, two chains being secured to a top portion of said door in a transversely spaced-apart relationship adjacent its ottfurnace sides, the other chain being secured to the top portion of said door at substantially its center and adjacent its furnace side and in a transversely spaced-apart and staggered relationship with respect to said pair of chains, each of said chains being operatively secured to a cooperating one of said winding drums, means for actuating said shaft to rotate said drums and raise and lower said door, the lengths of said chains being proportioned to position and raise and lower said door in an upwardly-. inwardly tilted relationship with respect to the furnace opening, and means guiding said door in its tilted relationship during its movement along said track.

Reterences Cited in the file of this patent UNITED STATES PATENTS 871,421 Koppers Nov. 19, 1907 1,366,779 Fox Jan. 25, 1921 2,270,484 Wallerius Jan. 20, 1942 2,387,594 Longenecker Oct. 23, 1945 2,494,713 Longenecker Ian. 17, 1950 2,594,188 Longenecker Apr. 22, 1952 FOREIGN PATENTS 289,150 Italy Oct. 6, 1931 

